Injection of eggs with fluid substances has typically been used to incubate certain vaccines which have medical applications, as eggs provide an appropriate environment for the growth of such vaccine materials. More recently, however, as developments in the field of poultry embryology have become more advanced, it has become desireable to add various substances to the embryo or to the environment around the embryo within an avian egg for the purpose of encouraging beneficial effects in the subsequently hatched chick. Such beneficial effects include increased growth, prevention of disease, increasing the percentage hatch of large numbers of incubated eggs, and otherwise improved physical characteristics of hatched poultry. Additionally, certain types of vaccination which could heretofore only be carried out upon either recently hatched or fully mature poultry, can now be successfully accomplished upon an embryonated egg.
One traditional method of injecting eggs has been injection by hand. Skilled operators can inject eggs by hand with some success, but the speed and accuracy of the process is limited. Additionally, hand injection of eggs, even by skilled operators, does not always result in continuous repeated precision delivery of materials to a desired particular location within an egg. Thus, practical techniques and methodologies for high speed precision application of active substances into eggs is a desirable development.
Additionally, where such injection techniques can replace hand injection of very young chicks (typically dayold chicks), beneficial increases in efficiency can be accomplished, and the stress of injection on chicks which are so young can be significantly reduced.
A number of automatic devices have been disclosed for injecting eggs. These include patents to Sandhage, U.S. Pat. No. 3,377,989 and to Miller, U.S. Pat. Nos. 4,040,388; 4,469,047; and 4,593,645. Additionally, a particularly successful injection device is disclosed in Hebrank U.S. Pat. No. 4,681,063 which is assigned to the assignee of the present invention. A review of all of these patents and their associated systems reveals, however, that all require that fluid be delivered to the egg through an injection needle and in turn that the fluid be delivered to the needle through a rather complicated system of pumps and tubing which carries the fluid from some type of stock storage to the needle.
As would be expected, when an injection device is placed in contact with a large number of eggs--which indeed is the purpose of such a machine--contamination of any one or more of the needles may occur. For example, a needle encountering an egg which has died during incubation can easily become contaminated by the materials in the dead egg. In turn, with the needle so contaminated, especially with biological impurities, it is likely that the tubing, stock supplies and other portions of the delivery system can likewise be contaminated. When this is the case, in order to prevent contamination of large number of eggs which are later handled and injected by the machine, it becomes necessary to halt the entire injection operation, and thoroughly clean, disinfect or otherwise renew the device, all before continuing with the injection the machine was intended for in the first place. As might be expected, the time spent clearing up any such problem drastically reduces the speed and efficiency for which the machine was intended.
As another consideration in egg injection, where specific vaccines or other sensitive materials are to be delivered, the specific quantity delivered is often an important parameter. This is especially true when very small quantities of materials must be delivered. For example, in some treatments of avian embryos, microliter quantities are often desired. The large systems of pumps and tubing used heretofore in injection machines makes accurate and precise delivery of such small quantities rather difficult.
Accordingly, it is an object of the invention to provide an automated injection system for embryos within eggs which has an advanced fluid delivery system which eliminates the pumping of fluids through conventional fluid handling systems and thereby reduces or eliminates the possibility of the contamination of the fluid and provides a more accurate volume delivery of such fluids.